The present invention relates to a method of vehicle operation and more particularly to vehicle operating strategies for use with chassis dynamometer testing.
During vehicle development, vehicles may be tested on chassis dynamometers, where the powered wheels are mounted on some type of roller system to allow the vehicle operations to be tested while the vehicle is stationary. Today's modern vehicles have many different computer controlled systems that, under normal operating conditions (normal mode), monitor and automatically change vehicle operation based on the monitored vehicle systems. There may be difficulty testing vehicles on a single roll chassis dynamometer when the vehicle controllers are set to operate under normal operating conditions because of the operation of anti-lock brake and other systems which will set malfunction indications when all four wheels are not turning. For hybrid vehicles in particular, such operation faults may inhibit proper testing of vehicle functions such as stop-start, regenerative brakes and other hybrid vehicle functions making the dynamometer test results non-representative of the emission and fuel economy of the vehicle under normal use on the road.
Accordingly, while operating a vehicle on a chassis dynamometer, vehicle operation algorithms may be employed to control the vehicle that are not active when the vehicle is operating under normal driving conditions. These dynamometer operation algorithms (dynamometer mode operation) enable the particular testing to be accomplished on the dynamometer. The dynamometer operation algorithms may also require additional component redundancy or complex algorithms to determine when to start and when to exit execution of the dynamometer control mode algorithms, which may support safe operation of the vehicle on the dynamometer and also assure the dynamometer mode is not activated when the vehicle is not on a dynamometer.